Reservoir Baffle Arrangement for a Vehicle Fuel Tank

ABSTRACT

A baffle arrangement for a vehicle fuel tank includes first and second wall portions, each having an inner end and an outer end and formed as a spiral of about 270 degrees. The first wall portion and second wall portion are positioned with the respective inner ends in opposed spaced relation to define a central reservoir, and with the respective outer ends spaced from the other wall portion to form inlets on opposite sides, the portions between the inner ends and outer ends defining passageways to the central reservoir.

FIELD OF THE INVENTION

The invention relates to vehicle fuel tanks, and more specifically, to a reservoir baffle arrangement for a vehicle fuel tank that allows use of more of the fuel tank volume. The invention has advantageous use in cylindrical fuel tanks as are used in heavy duty trucks.

BACKGROUND AND SUMMARY

Diesel powered trucks use externally mounted fuel tanks that are typically cylindrical in shape and mounted longitudinally on the truck frame. Because of the placement and length of the fuel filler neck, an upper portion of the tank volume is lost. In addition, depending on mounting of the draw tube, the orientation of the tube and the location of the tube mouth, a residual amount of fuel must remain in the tank to cover the draw tube mouth, so that the fuel pump can deliver fuel under all conditions. The residual amount of fuel in the bottom of the tank must accommodate tilting of the tank when the vehicle climbs or descends a grade.

Thus, the useful volume of the fuel tank is less than the total volume defined by the walls of the tank.

A disadvantage is that for a given fuel tank the range of the vehicle is less than it would be if more of the residual fuel volume could be used. From another point of view, the fuel tank may be considered to be larger than would be necessary if more of the residual volume could be used. Another disadvantage is that the vehicle weight may unnecessarily include the weight of the residual fuel volume and the added weight of the larger fuel tank.

The invention provides a device that allows the vehicle to use more of the residual fuel than a conventional fuel tank. Accordingly, a small fuel tank may be used which can save space on the frame, and the vehicle weight can be reduced.

A device according to the invention includes a first wall portion having an inner end and an outer end and formed as a spiral of about 270 degrees turning in a first direction and a second wall portion having an inner end and an outer end and formed as a spiral of about 270 degrees turning in a second direction opposite the first direction. The first wall portion and second wall portion are positioned with the respective inner ends in opposed spaced relation to define a central reservoir, and the respective outer ends are spaced from the other wall portion to form inlets on opposite sides, the portions between the inner ends and outer ends defining passageways to the central reservoir.

According to another aspect of the invention, a plane defining an interface between the inner end of the first wall portion and the inner end of the second wall portion is perpendicular to planes defining the inlets.

According to yet another aspect of the invention, a distance between the first wall portion and the second wall portion is greatest where the respective outer ends form the inlets and narrows as the passageways lead to the central reservoir.

According to the invention, the first wall portion and second wall portion are formed of sheet material and are perpendicular to a bottom of the baffle arrangement.

The invention also contemplates a fuel tank arrangement for a vehicle, including, a tank having a cylindrical outer wall defining an interior having an axial direction. A baffle arrangement is mounted in a bottom of the tank, the baffle arrangement having a first wall portion having an inner end and an outer end and formed as a spiral of about 270 degrees turning in a first direction, a second wall portion having an inner end and an outer end and formed as a spiral of about 270 degrees turning in a second direction opposite the first direction, the first wall portion and second wall portion positioned with the respective inner ends in opposed spaced relation to define a central reservoir, and with the respective outer ends spaced from the other wall portion to form inlets on opposite sides, the portions between the inner ends and outer ends defining passageways to the central reservoir, the baffle arrangement being is oriented so that the inlets open in the axial direction, and, a draw tube mounted to extend with a mouth in the central reservoir.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention will be better understood with reference to the appended drawings, in which:

FIG. 1 is a perspective view of an embodiment of a baffle arrangement in accordance with the invention;

FIG. 2 is a top view of the embodiment of FIG. 1; and,

FIG. 3 is an end view of a fuel tank showing schematically the orientation of a fuel draw tube with a baffle arrangement.

DETAILED DESCRIPTION OF THE INVENTION

FIG. 1 shows a perspective view of a baffle arrangement 5 for a fuel tank in accordance with the invention and FIG. 2 is a top view of the baffle arrangement of FIG. 1. The arrangement 5 includes a first wall 10 and a second wall 20 that are positioned vertically with respect to a floor or bottom 30. The first wall 10 is formed as a spiral of about 270° turning in a first direction from an outer edge 12 to an inner edge 14. The second wall 20 is formed also formed as a spiral of about 270°, but turning in a second direction opposite the first direction from an outer edge 22 to an inner edge 24.

The first wall 10 and second wall 20 are positioned in a nested arrangement with the respective inner ends 14, 24 in opposed spaced relation to define a central reservoir 40. The respective outer ends 12, 22 are spaced from the other wall portion to form inlets 50, 52 on opposite sides of the baffle arrangement 5. The respective walls 10, 20 between the inner ends and outer ends define passageways from the inlets 50, 52 to the central reservoir 40.

As shown in FIG. 3, the baffle arrangement 5 provides a reservoir at a bottom of a fuel tank 60, represented here as an end section of a cylindrical tank. A draw tube 62 is positioned with an inlet or mouth 64 disposed in the central reservoir 40 to draw fuel from the tank.

As will be recognized, the floor 30 of the baffle arrangement 5 will be formed with a curvature to fit without a gap on the bottom of the tank 60. Alternatively, the first wall 10 and second wall 20 may be mounted directly to the wall of the fuel tank 60.

The baffle arrangement 50 is mounted in a fuel tank (for example, the fuel tank 60) so that the inlets 50, 52 are open in the longitudinal or axial direction of the tank, which normally coincides with the front to back direction of the vehicle on which the tank is mounted. The broken line A in FIG. 2 indicates the longitudinal direction for mounting purposes.

As will be understood by those skilled in the art, the baffle arrangement of the invention may be used in a cylindrical tank as shown, or in tanks of other shapes, for example, D-shaped, rectangular, oval and the rest. The baffle arrangement will function optimally in a tank shaped so that fuel collects in or near the place the baffle is installed, for example, a tank that has a longitudinal dimension greater than a lateral dimension. The dimensions of the baffle itself, particularly the lateral dimensions, may be selected to optimize the collection of fuel, as will be understood.

As a vehicle moves, climbing or descending grades, accelerating or braking, turning left or right, fuel will move in the tank. If the fuel level is low, the baffle arrangement 5 will ensure that the mouth 64 of the draw tube 62 is covered so that fuel and not air is drawn into the fuel system. The curvature of the first wall 10 and second wall 20 and their respective positions form traps for moving fuel.

For example, when fuel may move forward and back, that is, along the axis A because of the vehicle is on a grade or is experiencing acceleration forces, one of the walls 10, 20 will act as a cup to trap fuel. The cup may be understood to be the portion between the outer edge 22 and inner edge 24, using the second wall 20 as an example. The first wall 10 between the outer edge 12 and inner edge 14 acts as a cup for fuel moving in the opposite direction.

It will be understood that fuel will fill the cup formed by a wall until the volume of fuel spills over the respective inner edge 14, 24 and out through the opposing passage. The working volume of the baffle arrangement 5 may be adjusted by changing the height of the walls 10, 12, the curvature of the spiral, and the relatively spacing between the walls.

For lateral movements of fuel in the tank, for example, during a turn, the portion of the wall 10 to the left of the axis A in FIG. 2, that is, between the inner edge 14 and where the axis A intersects the first wall 10 acts as trap fuel from flowing out of the reservoir 40. Correspondingly, the second wall 20 forms a trap for lateral fuel movements of the opposite direction between the inner edge 24 and the point where the axis A intersects the second wall 20.

The first wall 10 and second wall 20 are formed as smooth curves to facilitate the flow of fuel through and for simplicity in manufacturing. Alternatively, a baffle arrangement 105 may include walls 110, 120 formed as straight segments joined at corners as shown in FIG. 4. Note that the inner segment 114, 124 of each wall 110, 120 is generally perpendicular to the outer segment 112, 122 of the respective wall so that the same fuel trap arrangement is provided.

The invention has been described in terms of preferred embodiments, but those of skill in the art will understand that equivalents may be substituted without departing from the scope of the invention as defined in the appended claims. 

1. A baffle arrangement for a vehicle fuel tank, comprising: a first wall portion having an inner end and an outer end and formed as a spiral of about 270 degrees turning in a first direction; a second wall portion having an inner end and an outer end and formed as a spiral of about 270 degrees turning in a second direction opposite the first direction, the first wall portion and second wall portion positioned with the respective inner ends in opposed spaced relation to define a central reservoir, and with the respective outer ends spaced from the other wall portion to form inlets on opposite sides, the portions between the inner ends and outer ends defining passageways to the central reservoir.
 2. The baffle arrangement as claimed in claim 1, wherein a plane defining an interface between the inner end of the first wall portion and the inner end of the second wall portion is perpendicular to planes defining the inlets.
 3. The baffle arrangement as claimed in claim 1, wherein a width of the inlets is greater than a distance between the respective inner ends of the first wall portion and second wall portion.
 4. The baffle arrangement as claimed in claim 1, wherein the first wall portion and second wall portion are formed of sheet material and are perpendicular to a bottom of the baffle arrangement.
 5. The baffle arrangement as claimed in claim 1, wherein a distance between the first wall portion and the second wall portion is greatest where the respective outer ends form the inlets and narrows as the passageways lead to the central reservoir.
 6. The baffle arrangement as claimed in claim 1, wherein each wall portion is formed as a smooth curve.
 7. The baffle arrangement as claimed in claim 1, wherein each wall portion is formed as a series of straight wall segments.
 8. A fuel tank arrangement for a vehicle, comprising: a tank having an outer wall defining an interior having an axial direction; a baffle arrangement mounted in a bottom of the tank and having a first wall portion having an inner end and an outer end and formed as a spiral of about 270 degrees turning in a first direction, a second wall portion having an inner end and an outer end and formed as a spiral of about 270 degrees turning in a second direction opposite the first direction, the first wall portion and second wall portion positioned with the respective inner ends in opposed spaced relation to define a central reservoir, and with the respective outer ends spaced from the other wall portion to form inlets on opposite sides, the portions between the inner ends and outer ends defining passageways to the central reservoir; wherein, the baffle arrangement is oriented so that the inlets open in the axial direction; and, a draw tube mounted to extend with a mouth in the central reservoir. 